During the 1980's, the Versa Module European (VME) standard emerged to provide an open systems architecture in solving many of the problems with the form factor and interconnect method of earlier standards. VMEbus allows users to build a customized system in a standard chassis and backplane to suit their particular processing needs with off-the-shelf components with the assurance of interconnectivity and compatibility at the board level.
To further increase flexibility and provide additional processing functions while utilizing a single slot in the chassis, VMEbus carrier boards may include one or more connectors to accommodate electronic modules or mezzanine boards which may implement a wide variety of control, interface, input/output, analog, and digital functions. One example of such a mezzanine board is the INDUSTRYPACK (IP) manufactured by GreenSpring Computers, Inc. of Menlo Park, Calif.
One application utilizing a VMEbus architecture to provide flexibility and configurability in acquisition and processing of weather data from various weather satellites is the PanThor system developed and manufactured by the assignee of the present invention. Similarly, a Satellite Processing Interface Unit (SPIU) produced by the assignee of the present invention is a dedicated unit which provides digital frame synchronization, FIFO data buffering, parallel digital input/output, and some computing capability for acquiring and processing weather information. Although the SPIU utilizes field programmable gate arrays (FPGA's), the SPIU does not provide functions such as bit synchronization and analog input which may be required to receive data from various environmental satellites.